Saadat.123 has asked for the
wisdom of the Perl Monks concerning the following question:

Okay I am a typical VBA part-time programmer. Use VBA to solve a few problems. I have been using Perl/Java offtimes to find solutions and automation to a few tasks that I do. Now typically I'd use a database (access) and an SQL statement to get my results but I have been challenged not to use SQL.
I have a super list of data (A) and a sublist (B). I need to generate a list (C) that is in (A) but not in (B).... what would be the fastest way in perl?

Essentially the same question was asked today in removing a sublist.
You might like to check the answers given there and
perlfaq4 (arrays section)
and Perl Cookbook, recipe 4.8 "Finding elements in one array but not another".

Re performance, the way to find out is to use the Benchmark module to compare the running times of various solutions.